Metal-particle dispersion composition and aqueous coating composition

ABSTRACT

Provided is a metal-particle dispersion composition as a composition containing dispersed metal particles and being suitable for use in aqueous coating compositions, etc., the metal-particle dispersion composition comprising 10-80 mass % metal particles, 0.01-10 mass % organic titanate compound in a chelate form, 1-40 mass % water, and 2-30 mass % organic solvent having a higher boiling point than water, the amounts being based on the whole composition, wherein the organic titanate compound is an organic compound represented by Ti(OR)4 (the OR groups include at least one chelatable substituent based on triethanolamine) and the organic solvent having a higher boiling point than water is a C7 or lower alcohol compound.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a 371 application of the International PCTapplication serial no. PCT/JP2018/037358, filed on Oct. 5, 2018, whichclaims the priority benefit of Japan Patent Application No. 2017-197778,filed on Oct. 11, 2017. The entirety of each of the above-mentionedpatent applications is hereby incorporated by reference herein and madea part of this specification.

TECHNICAL FIELD

The present invention relates to a composition in which metal particlesare dispersed and an aqueous coating composition containing thecomposition.

BACKGROUND ART

In Patent Literature 1, an aqueous coating composition for rustprevention which contains, based on the entire coating composition, 10to 60 mass % of metal particles selected from among zinc particles, zincalloy particles, and aluminum particles, 1 to 15 mass % of an organictitanate compound in a chelate form, 20 to 60 mass % of water, and 2 to20 mass % of an organic solvent having a higher boiling point than wateris described.

CITATION LIST Patent Literature

-   [Patent Literature 1]    -   Japanese Patent No. 3636203

SUMMARY OF INVENTION Technical Problem

An objective of the present invention is to provide a composition inwhich metal particles are dispersed and which is suitably used for anaqueous coating composition described in Patent Literature 1. In thisspecification, “metal particles” refers to a particle materialcontaining a metal and/or an alloy. In addition, an objective of thepresent invention is to provide a coating composition containing such acomposition.

Solution to Problem

The inventors conducted extensive studies in order to address the aboveproblem, and as a result, the following new findings have been obtained.

When a dispersion solution is used (as a specific example, a case ofblending with other raw materials in order to produce a predeterminedcomposition is exemplified), metal particles need to be appropriatelydispersed in the dispersion solution. However, for the dispersionmethod, the simplest and most reliable method is a method of stirring adispersion solution. However, when a dispersion solution is stirred,collision between metal particles that float inside the dispersionsolution inevitably occurs. Collision between metal particles may causedefects such as cracking and breaking in the metal particles that havecollided.

In such defects, a new surface is generated in metal particles, and thenew surface comes into contact with water contained in a liquidcomponent of the dispersion solution and a chemical interaction iscaused. When the new surface interacts with water, a reaction in which ametallic material constituting metal particles is dissolved occurs, andhydrogen is generated as a counter reaction of the reaction. Since thesolubility of hydrogen in the dispersion solution is generally low,hydrogen generated when the metallic material dissolves is releasedoutside of the dispersion solution.

When the dispersion solution stored inside a sealed container is stirredby shaking the container or the like while a sealed state is maintained,since hydrogen generated in the above process accumulates in a gas partin the sealed container, the pressure in the sealed container increases.When the degree of the increase is large, the container swells and whenthe degree of the increase is too large, the sealed state of thecontainer cannot be maintained, and the content leaks from thecontainer. In particular, when an amount of hydrogen generated is large,fatal problems such as breakage of the container may occur. Such aphenomenon based on hydrogen generated due to collision between metalparticles inside the dispersion solution may occur when a storage periodis long even though the dispersion solution is simply stored in thesealed container without actively shaking the container.

The inventors have focused on the above phenomenon, and studied a methodof minimizing generation of hydrogen. As a result, the inventors newlyfound that, when a predetermined organic chelate compound is containedin a dispersion solution, generation of hydrogen can be significantlyminimized.

Based on the above findings, the present invention includes thefollowing aspects.

(1) A metal-particle dispersion composition containing, based on theentire composition, 10 to 80 mass % of metal particles, 0.01 to 10 mass% of an organic titanate compound in a chelate form, 1 to 40 mass % ofwater, and 2 to 30 mass % of an organic solvent having a higher boilingpoint than water, wherein the organic titanate compound is an organiccompound represented by Ti(OR)₄ (provided that OR groups include atleast one chelatable substituent based on triethanolamine), and whereinthe organic solvent having a higher boiling point than water is alcoholshaving 7 or less carbon atoms.(2) The metal-particle dispersion composition according to (1), whereina metallic material contained in the metal particles is composed of ametal or alloy including an element that satisfies either of being ableto form at least one of a water-insoluble oxide and a water-insolublehydroxide and being insoluble in water with a pH of 8 as a basematerial.(3) The metal-particle dispersion composition according to (1) or (2),wherein the OR groups include an alkoxy group and do not include ahydroxyl group.(4) The metal-particle dispersion composition according to (3), whereinthe OR groups include an alkoxy group having 4 or less carbon atoms andthe chelatable substituent based on triethanolamine.(5) The metal-particle dispersion composition according to any one of(1) to (4), wherein a proportion of the content of the organic titanatecompound with respect to the content of the metal particles is 0.5% ormore.(6) The metal-particle dispersion composition according to any one of(1) to (5), wherein a ratio of the number of carbon atoms N_(C) to thenumber of hydroxyl groups N_(OH) in the alcohols is 4 or less.(7) A metal-particle dispersion composition containing, based on theentire composition, 10 to 80 mass % of metal particles, 0.01 to 10 mass% of an organic titanate compound, 1 to 40 mass % of water, and 2 to 30mass % of an organic solvent having a higher boiling point than water,wherein the organic titanate compound is an organic compound representedby Ti(OR)₄ (provided that OR groups include at least one substituentbased on a pyrophosphate ester), and wherein the organic solvent havinga higher boiling point than water has 7 to 20 carbon atoms and has aplurality of ether bonds.(8) The metal-particle dispersion composition according to (7), wherein,in the substituent based on a pyrophosphate ester contained in theorganic titanate compound, the number of ester groups bonded to eachpyrophosphate is 1 or more and 2 or less.(9) The metal-particle dispersion composition according to (7) or (8),wherein the number of carbon atoms of each ester group bonded topyrophosphate is 5 or more.(10) The metal-particle dispersion composition according to any one of(7) to (9), wherein the number of ether bonds contained in the organicsolvent having a higher boiling point than water is 3 or more.(11) The metal-particle dispersion composition according to any one of(7) to (10), wherein the organic solvent having a higher boiling pointthan water contains a smaller number of hydroxyl groups than the numberof ether bonds.(12) An aqueous coating composition including the metal-particledispersion composition according to any one of (1) to (11).

Advantageous Effects of Invention

According to the present invention, there is provided a composition inwhich metal particles are dispersed and which is suitably used for anaqueous coating composition. In addition, there is provided an aqueouscoating composition containing metal particles based on such acomposition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates Table 13 of the evaluation results of Example 5.

FIG. 2 illustrates Table 14 of the evaluation results of Example 5.

FIG. 3 illustrates Table 15 of the evaluation results of Example 5.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below.

First Embodiment

A metal-particle dispersion composition according to one embodiment ofthe present invention contains metal particles, an organic titanatecompound in a chelate form, water, and an organic solvent having ahigher boiling point than water.

As described above, metal particles are a particle material containing ametal and/or an alloy. The metallic material contained in metalparticles is composed of a metal or alloy including an element thatsatisfies either of being able to form at least one of a water-insolubleoxide and a water-insoluble hydroxide and being insoluble in water witha pH of 8 as a base material. Specific examples of such metallicmaterials include metals and alloys including one, or two or moreelements selected from the group consisting of iron group elementshaving Fe, Co and Ni as constituent elements, platinum group elementshaving Pt, In, Rh and the like as constituent elements, noble metalshaving Au, Ag, and Cu as constituent elements, and Sn, Zn, Al, Ti, Cr,and Mn as a base material. The element serving as a “base material” inthis specification is a constituent element in the case of a metal, andmeans an element having the largest content (mass %) among elementsconstituting an alloy in the case of an alloy. Examples of an iron-basedalloy containing iron as a base material include stainless steel such asSUS304.

The shape of metal particles is not limited. The particles have a shapeclose to a true sphere or a flat shape. The size thereof is notparticularly limited, and is appropriately set according toapplications. A particle size (median diameter D50) at 50 volume % in acumulative distribution from the side of a small particle size measuredaccording to a laser diffraction and scattering method may exceed 100 μmor may be 10 μm or less. When a dispersant is used as a main componentfor appropriately dispersing metal particles in the metal-particledispersion composition, if the particle size is excessively large,appropriate dispersion may be difficult. On the other hand, since themetal-particle dispersion composition according to one embodiment of thepresent invention appropriately disperses metal particles due tostirring when used, the size of metal particles contained in themetal-particle dispersion composition is essentially arbitrary.

Generally, since the specific surface area increases when the particlesize (median diameter D50) of metal particles decreases, an area of allof the particles increases. Therefore, for example, when iron particleshave a particle size (median diameter) of under 53 μm mesh, since thereis a risk of ignition due to natural oxidation, special management isnecessary. Even if such iron particles that are easily oxidized arecontained as metal particles, in the metal-particle dispersioncomposition according to one embodiment of the present invention, sincean organic titanate compound appropriately protects metal particles aswill be described below, it is possible to appropriately minimize thegeneration of hydrogen.

The content (“content” in this specification means an amount based onthe entire composition containing a target object) based on the entirecomposition of metal particles in the metal-particle dispersioncomposition according to one embodiment of the present invention is 10mass % or more and 80 mass % or less. When the content of metalparticles is too small, it is difficult to increase the content of metalparticles in the composition using the metal-particle dispersioncomposition as a raw material. When the content of metal particles isexcessive, it is difficult to appropriately secure the content ofcomponents other than metal particles contained in the metal-particledispersion composition such as the content of an organic titanatecompound to be described below.

The organic titanate compound refers to an organic compound representedby a general formula of Ti(OR)₄. Here, OR groups are selected from amonga hydroxyl group, a lower alkoxy group, and a chelatable substituent,and may be the same or different from each other, but include at leastone chelatable substituent.

The lower alkoxy group refers to an alkoxy group having 6 or less carbonatoms and preferably 4 or less carbon atoms such as methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy, and tert-butoxy groups. Thelower alkoxy group of the organic titanate compound is easily hydrolyzedat room temperature under an aqueous environment to form a hydroxylgroup (OH group).

The chelatable substituent refers to a group derived from an organiccompound having a chelate-forming ability. Examples of such an organiccompound include β-diketones such as acetylacetone, alkyl carbonylcarboxylic acids such as acetoacetic acid and esters thereof, hydroxyacids such as lactic acid, and alkanolamines such as triethanolamine.Specific examples of chelatable substituents include lactate, ammoniumlactate, triethanolaminate, acetylacetonate, acetoacetate, and ethylacetoacetate. Unlike a lower alkoxy group, such a chelatable substituentbonded to an organic titanate compound is unlikely to be hydrolyzed atroom temperature under an aqueous environment, but is hydrolyzed whenheated to a high temperature.

The chelatable substituents contained in the organic titanate compoundof the metal-particle dispersion composition according to one embodimentof the present invention are substituents in which at least one is basedon triethanol, that is, triethanolaminate. When the organic titanatecompound containing such a chelatable substituent is included, themetal-particle dispersion composition according to one embodiment of thepresent invention generates specifically a small amount of hydrogen gas.

The organic titanate compound includes triethanolaminate, in otherwords, it has a chelate form because at least one of OR groups istriethanolaminate. At least one of the other OR groups is a hydroxylgroup or a lower alkoxy group, and preferably a lower alkoxy group inorder to secure the bond between the organic titanate compound and thesurface of metal particles. In the regard, a preferable organic titanatecompound is a compound in which two OR groups are lower alkoxy groupsthat are easily hydrolyzed at room temperature and the remaining two ORgroups are chelatable substituents that are not easily hydrolyzed atroom temperature. Specific examples of such an organic titanate compoundinclude di-n-butoxytitanium bis(triethanolaminate), anddiisopropoxybis(triethanolaminate)titanium.

In the metal-particle dispersion composition according to one embodimentof the present invention, a hydroxyl group of the organic titanatecompound and a lower alkoxy group that is easily hydrolyzed at roomtemperature to form a hydroxyl group undergo a condensation reactionwith a hydroxyl group present on the surface of metal particles and thusorganic titanate molecules are more firmly bonded to the surface ofmetal particles according to chemical bonding. As a result, the surfaceof metal particles is covered with titanate molecules, and directcontact between metal particles and water is minimized. However, in thisstate, since the surface of metal particles is covered with atriethanolaminate group of the organic titanate compound, the pH of aliquid part in the metal-particle dispersion composition is about 8. Inthis state, even if defects occur in metal particles due to collisionbetween the metal particles and a new surface is generated, hydroxidesand oxides of the metallic material constituting metal particles arequickly generated, and cover the new surface, and thus dissolution ofthe metallic material can be stopped.

The lower limit value of the amount of the organic titanate compound isset based on the area of metal particles so that the organic titanatecompound can appropriately cover the surface of metal particles. When acombination of the organic titanate compound and the organic solvent isappropriately selected, since the solubility of the organic titanatecompound can be sufficiently increased, the upper limit is notsubstantially set. When the content of metal particles is 10 mass % ormore and 80 mass % or less as described above, it may be in a range of0.01 mass % to 10 mass %. A proportion (percentage) of the content ofthe organic titanate compound with respect to the content of metalparticles is preferably 0.5% or more, more preferably 1% or more, andparticularly preferably 2% or more.

The metal-particle dispersion composition according to one embodiment ofthe present invention contains water and an organic solvent having ahigher boiling point than water. Water is necessary because theinteraction between the organic titanate compound and the surface ofmetal particles includes hydrolysis of the organic titanate compound.The organic solvent having a higher boiling point than water isnecessary in order for an organic titanate compound having a chelatablesubstituent based on triethanolamine to be dissolved in themetal-particle dispersion composition. In this regard, the organicsolvent is alcohols having 7 or less carbon atoms. Specific examples ofalcohols having 7 or less carbon atoms include ethanol, n-propanol,2-propanol, propylene glycol monoethyl ether, diethylene glycol,triethylene glycol, propylene glycol, dipropylene glycol, anddipropylene glycol monoethyl ether. The number of carbon atoms ofalcohols is preferably 6 or less, more preferably 5 or less, still morepreferably 4 or less, and particularly preferably 3 or less. Inaddition, the number of carbon atoms of alcohols is preferably 2 ormore. The number of hydroxyl groups contained in such alcohols may beone or plural. In addition, alcohols having 4 or less carbon atoms mayhave an alkoxy group. A ratio (N_(C)/N_(OH)) of the number of carbonatoms N_(C) to the number of hydroxyl groups N_(OH) in alcohols ispreferably 4 or less, more preferably 3.5 or less, and particularlypreferably 3 or less.

The content of water and the content of the organic solvent are set sothat hydrolysis of the organic titanate compound is appropriately causedand the organic titanate compound is dissolved, and specifically, thecontent of water is 1 mass % or more and 40 mass % or less, and thecontent of the organic solvent having a higher boiling point than wateris 2 mass % or more and 30 mass % or less.

The pH of the metal-particle dispersion composition according to oneembodiment of the present invention is alkaline based on triethanolaminerelated to the organic titanate compound. The pH of the metal-particledispersion composition is preferably 7.5 or more, and more preferably7.5 or more and 8.5 or less. When the pH of the metal-particledispersion composition satisfies the above condition, hydrogen isunlikely to be generated even if a new surface is generated in metalparticles due to, for example, stirring of the metal-particle dispersioncomposition.

Second Embodiment

A metal-particle dispersion composition according to a second embodimentof the present invention contains metal particles, an organic titanatecompound, water, and an organic solvent having a higher boiling pointthan water, like the metal-particle dispersion composition according tothe first embodiment, and has a different type of the organic titanatecompound and a different type of the organic solvent having a higherboiling point than water compared to the metal-particle dispersioncomposition according to the first embodiment. Therefore, in thefollowing description, only the organic titanate compound and theorganic solvent having a higher boiling point than water will bedescribed.

The organic titanate compound contained in the metal-particle dispersioncomposition according to the second embodiment is an organic compoundrepresented by Ti(OR)₄, and the OR group contains at least onesubstituent based on a pyrophosphate ester. The OR group preferablycontains two substituents based on a pyrophosphate ester and morepreferably three substituents.

Since the organic titanate compound has a substituent based on apyrophosphate ester, the metal-particle dispersion composition tends tobe weakly acidic (4 or more and less than 7). It is considered that, inthe weakly acidic environment, oxygen (O) contained in pyrophosphateinteracts with metal particles, and in some cases, when metal elementsconstituting metal particles and a substance such as a phosphate areformed, generation of hydrogen according to the reaction between metalparticles and water is minimized in the metal-particle dispersioncomposition.

A pyrophosphate is a tetravalent acid, and one of which bonds to Ti, anda maximum of three ester bonds can be formed. When the number of esterbonds in the organic titanate compound is larger, the interaction of theorganic titanate compound with the organic solvent can be improved. Onthe other hand, when the number of esters bonded to pyrophosphate of theorganic titanate compound is too large, oxygen (O) contained inpyrophosphate is unlikely to interact with metal particles. In thesubstituent based on a pyrophosphate ester contained in the organictitanate compound according to one embodiment of the present invention,the number of ester groups bonded to each pyrophosphate is preferably 1or more and 2 or less.

When an organic group is not ester-bonded to P bonded to Ti via Obetween two Ps constituting pyrophosphate, and a hydroxyl group isbonded thereto, this is preferable because a substituent based on apyrophosphate ester is easily bonded to Ti.

The number of carbon atoms of each ester group bonded to pyrophosphateis preferably 5 or more and more preferably 7 or more in order toimprove the interaction with the organic solvent. In order to minimizethe influence of steric hindrance, the number of carbon atoms of eachester group bonded to pyrophosphate is preferably 15 or less, and morepreferably 12 or less.

The organic solvent having a higher boiling point than water containedin the metal-particle dispersion composition according to the secondembodiment has 7 to 20 carbon atoms and has a plurality of ether bonds.When the number of carbon atoms is 7 or more, it is easy to set aboiling point of the organic solvent to be higher than that of water.When the number of carbon atoms is 20 or less, the interaction betweenwater or an organic solvent and the organic titanate compound easilyoccurs.

The number of ether bonds contained in the organic solvent having ahigher boiling point than water is preferably 3 or more in order toimprove miscibility of the organic solvent with water. Although theupper limit of the number of ether bonds contained in the organicsolvent having a higher boiling point than water is not set, since theupper limit of the number of carbon atoms of the organic solvent havinga higher boiling point than water is 20, the number of ether bondscontained in the organic solvent having a higher boiling point thanwater is preferably 10 or less in order to secure stability of thestructure and secure ease of production.

While the organic solvent having a higher boiling point than water maycontain a hydroxyl group in order to improve miscibility of the organicsolvent with water, the number of hydroxyl groups is preferably smallerthan the number of ether bonds. When the number of hydroxyl groups islimited, it is possible to reduce a possibility of active hydrogencontained in the hydroxyl group acting to reduce the stability of themetal-particle dispersion composition. In this regard, when the organicsolvent having a higher boiling point than water contains a hydroxylgroup, the number of hydroxyl groups is preferably 1.

Even if the metal-particle dispersion composition according to someembodiments of the present invention described above are stored for along time, since hydrogen is unlikely to be generated, they can besuitably used as a raw material of a composition having a relatively lowcontent of metal particles than the metal-particle dispersioncomposition. As such a composition, an aqueous coating compositiondescribed in Patent Literature 1 may be exemplified.

The embodiments described above are described to facilitate theunderstanding of the present invention, and are not described to limitthe present invention. Therefore, components disclosed in the aboveembodiments are intended to include all design changes and equivalentsin the technical scope of the present invention.

EXAMPLES

While the effects of the present invention have been described belowwith reference to examples, the present invention is not limitedthereto.

Example 1

A metal-particle dispersion composition containing 3 g of water, 2 g ofany organic solvent shown in Table 1, 1 g of any organic titanatecompound shown in Table 2, and 3 g of any metal particles shown in Table3 was prepared (Table 4).

TABLE 1 Product name, Number etc. Chemical name Production OS-1 HisolveEDM Diethylene TOHO Chemical glycol ethyl Industry Co., Ltd. methylether OS-2 Hisolve MTEM Tetraethylene glycol dimethyl ether OS-3 PrGPropylene glycol AGC Inc. OS-4 DPrG Dipropylene glycol OS-5 PM Propyleneglycol Dow Chemical monoethyl ether Japan OS-6 DPM DiPropylene glycolDow Chemical monoethyl ether Japan OS-7 Ethanol Wako Pure ChemicalIndustries, Ltd. OS-8 n-Propanol Wako Pure Chemical Industries, Ltd.OS-9 2-Propanol Wako Pure Chemical Industries, Ltd. OS-10 1 -ButanolWako Pure Chemical Industries, Ltd. OS-11 n-Pentanol Wako Pure ChemicalIndustries, Ltd. OS-12 2-Pentanol Wako Pure Chemical Industries, Ltd.

TABLE 2 Product name, Number etc. Chemical name Production OTC-1 OrgatixTA-10 Titanium tetraisopropoxide Matsumoto Fine OTC-2 Orgatix TA-22Butyl titanate dimer Chemical Co., OTC-3 Orgatix TA-25 Tetra normalbutyl titanate Ltd. OTC-4 Orgatix TC-100 Titanium acetylacetonate OTC-5Orgatix TC-300 Titanium lactate ammonium salt OTC-6 Orgatix TC-315Titanium lactate OTC-7 Orgatix TC-400 Titanium triethanol aminate OTC-8Orgatix TC-510 Titanium aminoethyl aminoethanolate OTC-9 Orgatix TC-750Titanium ethyl acetoacetate OTC-10 TAT Di-n-butoxybis(triethanol NipponSoda aminate)titanium Co., Ltd. OTC-11 B10 Tetrabutoxy titanium oligomerOTC-12 TOG Titanium-i-propoxyoctylene glycolate

TABLE 3 Product name, Composition, shape (median Number etc.diameterD50) Production MP-1 Zinc Flake GTT Zn flake (D50 = 13 μm, under45 μm ECKART GmbH mesh) MP-2 Cr fine powder 10 μm Cr (10 μm) KojundoChemical Lab. Co., Ltd. MP-3 Cu powder ca. 5 μm Cu (5 μm) MP-4 Cu powderca. 1 μm Cu (1 μm) MP-5 SUS304 powder 150 μm SUS304 (under 150 μm mesh)pass MP-6 In powder 45 μm pass In (45 μm) MP-7 Mn powder 45 μm pass Mn(45 μm) MP-8 Mn fine powder 10 μm Mn (10 μm) MP-9 Zinc Flake GTT Znflake (D50 = 13 μm, under 45 μm ECKART GmbH mesh) MP-10 #350 Sn flakeFukuda Metal Foil & Powder Co., Ltd. MP-11 Ni_Flake Type HCA-1 Nifilament, flake Nikko Rica Corporation MP-12 Al powder ca. 30 μm Alamorphous particles Kojundo Chemical Lab. Co., Ltd. MP-13 Fe powder 53μm pass Fe flake approximation (under 53 μm mesh) MP-14 Fe powder 3 μm~5μm Fe spherical shape (3 μm to 5 μm) MP-15 Ti powder 45 μm pass Tiamorphous mass (under 45 μm mesh) MP-16 V powder 75 μm pass V amorphousmass (under 75 μm mesh) MP-17 Ag powder ca. 1 μm Ag spike-like amorphose(1 μm) MP-20 M31 (Ag 1 μm to 3 μm) Ag spike-like amorphose (1 μm to 3μm) MP-21 Al powder ca. 3 μm Al amorphous particles MP-22 Co fine powderca. 5 μm Co filamentshape (5 μm) MP-23 Zn powder 75 μm pass Zn sphericalshape (under 75 μm mesh) MP-24 Zn powder ca. 7 μm Zn amorphous particles(7 μm) MP-25 Ni_10 μm Ni filament flake (10 μm)

TABLE 4 Organic Organic chelate Metal Evaluation solvent compoundparticles result Outline Example 1-1 OS-3 OTC-1 MP-1 D ComparativeExample Example 1-2 OTC-2 E Comparative Example Example 1-3 OTC-3 DComparative Example Example 1-4 OTC-4 D Comparative Example Example 1-5OTC-5 D Comparative Example Example 1-6 OTC-6 D Comparative ExampleExample 1-7 OTC-7 A Example of the present invention Example 1-8 OTC-8 DComparative Example Example 1-9 OTC-9 D Comparative Example Example 1-10OTC-10 A Example of the present invention Example 1-11 OTC-11 DComparative Example Example 1-12 OTC-12 E Comparative Example Example1-13 OS-1 OTC-7 E Comparative Example Example 1-14 OTC-10 E ComparativeExample Example 1-15 OS-2 OTC-7 E Comparative Example Example 1-16OTC-10 E Comparative Example Example 1-17 OS-4 OTC-7 A Example of thepresent invention Example 1-18 OTC-10 B Example of the present invention

The obtained metal-particle dispersion composition was put into a samplebottle (capacity: 14 ml) that can be fitted and sealed with a lid, andstirred in a sealed state for 1 minute under a room temperatureenvironment. After stirring, the sample was left and evaluated accordingto the following evaluation criteria. The evaluation results are shownin Table 4.

A: Generation of a gas was not visually observed even when 7 days hadpassed from when it was left.

B: Generation of a gas was visually observed within 7 days after 5 dayshad passed from when it was left.

C: Generation of a gas was visually observed within 5 days after 4 dayshad passed from when it was left.

D: Generation of a gas was visually observed within 4 days from when itwas left.

E: Turbidity was observed in a solution part when it was left, and theorganic titanate compound was not appropriately dissolved.

As shown in Table 4, in a metal-particle dispersion compositionaccording to Example 1-7 containing OTC-7 and a metal-particledispersion composition according to Example 1-10 containing OTC-10,which were an organic titanate compound having a chelating substituentbased on triethanolamine, when an organic solvent composed of alcoholshaving 6 or less carbon atoms having a higher boiling point than waterwas used, the organic titanate compound was appropriately dissolved, andeven if 5 days or longer had passed from when it was left afterstirring, generation of a gas was not observed. Here, in Table 1, in themetal-particle dispersion composition determined as “A”, even if 200days or longer had passed from when it was left after stirring,generation of a gas was not observed. Both a metal-particle dispersioncomposition according to Example 1-7 and a metal-particle dispersioncomposition according to Example 1-10 had a pH of 8, and zinc, which wasa base material of metal particles, easily formed a hydroxide (Zn(OH)₂)at that pH, and thus it is thought that hydrogen was unlikely to begenerated even if stirring was performed.

Here, while the pH of a metal-particle dispersion composition accordingto Example 1-8 containing an organic titanate compound of OTC-8 was 8.5,since the organic titanate compound of OTC-8 had a NH₂ group at theterminal of the chelating substituent, the solubility in the solvent wasrelatively low, and there was a possibility of an appropriate protectivefilm not being formed on metal particles. In addition, while the pH of ametal-particle dispersion composition according to Example 1-5containing an organic titanate compound of OTC-5 was 7.5, the organictitanate compound of OTC-5 was a compound having no alkoxy group andhaving a hydroxyl group. Therefore, it was not possible to exhibitappropriate solubility in a solvent related to a hydrolysis condensationreaction rate, and there was a possibility of an appropriate protectivefilm not being formed on metal particles

Example 2

A metal-particle dispersion composition containing 3 g of water, 2 g ofany organic solvent shown in Table 1, 3 g of any metal particles shownin Table 3, and any organic titanate compound shown in Table 2 in anamount corresponding to 2 wt % of metal particles was prepared (Table5). In addition, a metal-particle dispersion composition having the samecomposition but containing no organic titanate compound was prepared(Table 5).

TABLE 5 Organic Organic chelate Metal Evaluation solvent compoundparticles result Outline Example 2-1 OS-3 Not MP-2 D Comparativecontained Example Example 2-2 OTC-7 S Example of the present inventionExample 2-3 Not MP-3 D Comparative contained Example Example 2-4 OTC-7 SExample of the present invention Example 2-5 Not MP-4 E Comparativecontained Example Example 2-6 OTC-7 C Example of the present inventionExample 2-7 Not MP-5 S Reference contained Example Example 2-8 OTC-7 SExample of the present invention Example 2-9 Not MP-6 D Comparativecontained Example Example 2-10 OTC-7 S Example of the present inventionExample 2-11 Not MP-7 D Comparative contained Example Example 2-12 OTC-7B Example of the present invention Example 2-13 Not MP-8 D Comparativecontained Example Exampl 2-14 OTC-7 B Example of the present inventionExample 2-15 Not MP-9 E Comparative contained Example Example 2-16 OTC-7S Example of the present invention Example 2-17 Not MP-10 D Comparativecontained Example Example 2-18 OTC-7 S Example of the present inventionExample 2-19 Not MP-11 D Comparative contained Example Example 2-20OTC-7 S Example of the present invention Example 2-21 Not MP-12 DComparative contained Example Example 2-22 OTC-7 A Example of thepresent invention Example 2-23 Not MP-13 S Reference contained ExampleExample 2-24 OTC-7 S Example of the present invention Example 2-25 NotMP-14 D Comparative contained Example Example 2-26 OTC-7 S Example ofthe present invention Example 2-27 Not MP-15 D Comparative containedExample Example 2-28 OTC-7 S Example of the present invention Example2-29 Not MP-16 E Comparative contained Example Example 2-30 OTC-7 EReference Example Example 2-31 Not MP-17 E Comparative contained ExampleExample 2-32 OTC-7 C Example of the present invention

The obtained metal-particle dispersion composition was put into a samplebottle (capacity: 14 ml) that can be fitted and sealed with a lid, andstirred in a sealed state for 1 minute under a room temperatureenvironment. After stirring, the sample was left and evaluated accordingto the following evaluation criteria. The evaluation results are shownin Table 5.

S: Generation of a gas was not visually observed even when 60 days hadpassed from when it was left.

A: Generation of a gas was not visually observed even when 7 days hadpassed from when it was left.

B: Generation of a gas was visually observed within 7 days after 5 dayshad passed from when it was left.

C: Generation of a gas was visually observed within 5 days after 4 dayshad passed from when it was left.

D: Generation of a gas was visually observed within 4 days from when itwas left.

E: Generation of a gas was observed during stirring.

As shown in Table 5, when OTC-7 as an organic titanate compound having achelating substituent based on triethanolamine was contained, it waspossible to significantly reduce a possibility of generating a gas.Here, when metal particles had a non-conductor forming ability (MP-5),even if OTC-7 was not contained (Example 2-7), there was a possibilityof generation of a gas being minimized. In addition, when metalparticles were iron particles having a relatively large particle size(MP-13), since a specific surface area of metal particles was relativelysmall, an area of a new surface generated in the metal-particledispersion composition due to stirring was relatively small, and even ifno OTC-7 was contained (Example 2-23), there was a possibility ofgenerating a gas being minimized. When the base material of metalparticles was V (MP-16), if the pH of the metal-particle dispersioncomposition was 8, V₂O₄, an incomplete oxide of V, was formed togetherwith partially protonated vanadate ions (H₂VO₄ ⁻). Therefore, it isthought that gas generation easily occurred. When the base material ofmetal particles was Ag (MP-17), if OTC-7 was not contained (Example2-31), a gas was generated from the metal-particle dispersioncomposition during stirring. Since the pH of the metal-particledispersion composition was 8, no metal was dissolved based on a generalpotential-pH diagram, but a large specific surface area may have had aneffect because the particle size (median diameter D50) was as small asabout 1 μm. Even in a state in which the solubility of metal particlesincreased in this manner, when OTC-7 was contained, it was possible toappropriately minimize generation of a gas from the metal-particledispersion composition.

Example 3

A metal-particle dispersion composition containing 3 g of water, 2 g ofany organic solvent shown in Table 1, 3 g of any metal particles shownin Table 3, and any organic titanate compound shown in Table 2 in anamount corresponding to 2 wt % of metal particles was prepared (Table6). In addition, a metal-particle dispersion composition having the samecomposition but containing no organic titanate compound was prepared(Table 6).

TABLE 6 Organic Organic chelate Metal Evaluation solvent compoundparticles result Outline Example 3-1 OS-5 Not MP-9 D Comparativecontained Example Example 3-2 OTC-7 S Example of the present inventionExample 3-3 OS-6 Not D Comparative contained Example Example 3-4 OTC-7 CExample of the present invention Example 3-5 OS-7 Not D Comparativecontained Example Example 3-6 OTC-7 S Example of the present inventionExample 3-7 OS-8 Not D Reference contained Example Example 3-8 OTC-7 SExample of the present invention Example 3-9 OS-9 Not D Comparativecontained Example Example 3-10 OTC-7 S Example of the present inventionExample 3-11 OS-10 Not D Comparative contained Example Example 3-12OTC-7 S Example of the present invention Example 3-13 OS-11 Not DComparative contained Example Example 3-14 OTC-7 D Comparative ExampleExample 3-15 OS-12 Not D Comparative contained Example Example 3-16OTC-7 B Example of the present invention

The obtained metal-particle dispersion composition was put into a samplebottle (capacity: 14 ml) that can be fitted and sealed with a lid, andstirred in a sealed state for 1 minute under a room temperatureenvironment. After stirring, the sample was left and evaluated accordingto the following evaluation criteria. The evaluation results are shownin Table 6.

S: Generation of a gas was not visually observed even when 60 days hadpassed from when it was left.

A: Generation of a gas was not visually observed even when 7 days hadpassed from when it was left.

B: Generation of a gas was visually observed within 7 days after 5 dayshad passed from when it was left.

C: Generation of a gas was visually observed within 5 days after 4 dayshad passed from when it was left.

D: Generation of a gas was visually observed within 4 days from when itwas left.

E: Generation of a gas was observed during stirring.

Example 4

The following phosphoric acid organic titanate compound was prepared.

“Plenact 38S” (commercially available from Ajinomoto Fine-Techno Co.,Inc.)

Isopropoxy tri(dioctyl pyrophosphate)titanate

Reactive group: (H₃C)₂CH—O—

Functional group: —O—P(═O)(OH)—O—(═O)(OC₈H₁₇)₂

Composition active component: 90 wt % or more

-   -   2-propanol: 5 to 10 wt %    -   Toluene: 1.9 wt %

“Plenact 138S” (commercially available from Ajinomoto Fine-Techno Co.,Inc.)

Bis(dioctyl pyrophosphate)oxyacetate titanate

Reactive group: O═C(CH₂O—)O—

Functional group: —O—P(═O)(OH)—O—(═O)(OC₈H₁₇)₂

Composition active component: 90 wt % or more

-   -   2-propanol: 5 to 10 wt %    -   Toluene: 1.9 wt %

“Plenact 238S” (commercially available from Ajinomoto Fine-Techno Co.,Inc.)

Bis(dioctyl pyrophosphate)ethylene titanate

Reactive group: (CH₂O—)₂

Functional group: —O—P(—O)(OH)—O—(═O)(OC₈H₁₇)₂

Composition active component: 80 to 90 wt %

-   -   2-propanol: 10 to 20 wt %    -   Toluene: 1.4 wt %

“Plenact 338X” (commercially available from Ajinomoto Fine-Techno Co.,Inc.)

isopropyl tri(dioctyl pyrophosphate) titanate

Reactive group: CH₃(CH₃)(H)C—

Functional group: —O—P(═O)(OH)—O—(═O)(OC₈H₁₇)₂

Composition active component: 80 to 90 wt %

-   -   2-propanol: 10 to 20 wt %    -   Toluene: 1.5 wt %

Solvents shown in Table 7 were prepared.

TABLE 7 Product name Manufacturer Structure Structural formula HisolveEDE TOHO Diethylene glycol C2H5O Chemical ethyl methyl ether(CH2CH2O)2C2H5 Industry Co., Ltd. Hisolve MPM TOHO Polyethylene glycolC2H5O Chemical dimethyl ether (CH2CH2O)nC2H5 Industry Co., Ltd. HisolveMTEM TOHO Tetraethylene glycol CH3O (CH2CH2O)4CH3 Chemical dimethylether Industry Co., Ltd. Ethyl lactate TOHO Ethyl lactate CH3CH(OH)COOC2H5 Chemical Industry Co., Ltd. PrG AGC Inc. Propylene glycolHOCH2CH (OH)CH3 DPrG AGC Inc. Dipropylene glycol [CH3CH (OH)CH2]2ODowanol PM Dow Propylene glycol CH3OC3H6OH Chemcial monomethyl etherCo., Ltd. Dowanol DPM Dow DiPropylene glycol CH3O (C3H6O)2H Chemcialmonomethyl ether Co., Ltd. Dowanol PnB Dow Propylene glycol C4H9OC3H6OHChemcial n-butyl ether Co., Ltd. Dowanol PMA Dow Propylene glycolCH3OC3H6OCOCH3 Chemcial monomethyl ether Co., Ltd. acetate Dowanol TPMDow Tripropylene glycol CH3O (C3H6O)3H Chemcial methyl ether Co., Ltd.Dowanol DPnB Dow DiPropylene glycol C4H9O (C3H6O)2H Chemcial n-butylether Co., Ltd. Dowanol PPh Dow Propylene glycol C6H5OC3H6OH Chemcialphenyl ether Co., Ltd. Carbitol LG Dow Diethylene glycol CH3CH2O(CH2CH2O)2H Chemcial monoethyl ether Co., Ltd.

0.2 g of “Plenact 38S” was added to 2 g of any organic solvent shown inTable 7, and properties were observed. The results are shown in Table 8.

TABLE 8 Product Collection Product Amount name Manufacturer Structureamount name Manufacturer Structure added Hisolve TOHO Diethylene 2 gPlenact Ajinomoto isopropoxy tri 0.2 g EDE Chemical glycol ethyl 38SFine-Techno (dioctyl Industry Co., methyl pyrophosphate Ltd. etherester) Hisolve TOHO Polyethylene 2 g MPM Chemical glycol Industry Co.,dimethyl Ltd. ether Hisolve TOHO Tetraethylene 2 g MTEM Chemical glycolIndustry Co., dimethyl Ltd. ether Ethyl TOHO Ethyl 2 g lactate Chemicallactate Industry Co., Ltd. PrG AGC Inc. Propylene 2 g glycol DPrG AGCInc. Dipropylene 2 g glycol Dowanol Dow Chemcial Propylene 2 g PM Co.,Ltd. glycol monomethyl ether Dowanol Dow Chemcial DiPropylene 2 g DPMCo., Ltd. glycol monomethyl ether Dowanol Dow Chemcial Propylene 2 g PnBCo., Ltd. glycol n-butyl ether Dowanol Dow Chemcial Propylene 2 g PMACo., Ltd. glycol monomethyl ether acetate Dowanol Dow ChemcialTripropylene 2 g TPM Co.. Ltd. glycol methyl ether Dowanol Dow ChemcialDiPropylene 2 g DPnB Co., Ltd. glycol n-butyl ether Dowanol Dow ChemcialPropylene 2 g PPh Co., Ltd. glycol phenyl ether Carbitol Dow ChemcialDiethylene 2 g LG Co., Ltd. glycol monoethyl ether Product ImmediatelyAfter3 After 1 After 2 After 4 After 7 After 18 name after addition hrday days days days days Hisolve ∘ ← ← ← ← ← ← EDE (known) Hisolve ∘ ← ←← ← ← ← MPM (known) Hisolve ∘ ← ← ← ← ← ← MTEM (known) Ethyl ∘orange ← ←← ← ← ← lactate PrG x ← ← ← ← ← ← (known) DPrG x ← ← ← ← ← ← (known)Dowanol ∘orange ← ← ← ← ← ← PM Dowanol ∘yellow ← ← ← ← ← ← DPM Dowanol ∘← ← ← ← ← ← PnB Dowanol ∘ ← ← ← ← ← ← PMA Dowanol ∘ ← ← ← ← ← ← TPMDowanol ∘ ← ← ← ← ← ← DPnB Dowanol ∘ ← ← ← ← ← ← PPh Carbitol ∘ ← ← ← ←← ← LG

0.2 g of “Plenact 138S” was added to 2 g of any organic solvent shown inTable 7, and properties were observed. The results are shown in Table 9.

TABLE 9 Product Collection Product Amount name Manufacturer Structureamount name Manufacturer Structure added Hisolve TOHO Diethylene 2 gPlenact Ajinomoto Bis(dioctyl 0.2 g EDE Chemical glycol ethyl 238SFine-Techno pyrophosphate Industry Co., methyl ester)glycol Ltd. ethertitanate Hisolve TOHO Polyethylene 2 g MPM Chemical glycol Industry Co.,dimethyl Ltd. ether Hisolve TOHO Tetraethylene 2 g MTEM Chemical glycolIndustry Co., dimethyl Ltd. ether Ethyl TOHO Ethyl 2 g lactate Chemicallactate Industry Co., Ltd. PrG AGC Inc. Propylene 2 g glycol DPrG AGCInc. Dipropylene 2 g glycol Dowanol Dow Chemcial Propylene 2 g PM Co.,Ltd. glycol monomethyl ether Dowanol Dow Chemcial DiPropylene 2 g DPMCo., Ltd. glycol monomethyl ether Dowanol Dow Chemcial Propylene 2 g PnBCo., Ltd. glycol n-butyl ether Dowanol Dow Chemcial Propylene 2 g PMACo., Ltd. glycol monomethyl ether acetate Dowanol Dow ChemcialTripropylene 2 g TPM Co., Ltd. glycol methyl ether Dowanol Dow ChemcialDiPropylene 2 g DPnB Co., Ltd. glycol n-butyl ether Dowanol Dow ChemcialPropylene 2 g PPh Co., Ltd. glycol phenyl ether Carbitol Dow ChemcialDiethylene 2 g LG Co., Ltd. glycol monoethyl ether Product ImmediatelyAfter3 After 1 After 2 After 4 After 7 After 18 name after addition hrday days days days days Hisolve ∘ ← ← ← ← ← ← EDE (known) Hisolve ∘ ← ←← ← ← ← MPM (known) Hisolve ∘ ← ← ← ← ← ← MTEM (known) Ethyl ?orange/ ∘yellow/ ← ← ← ← ← lactate muddy clear PrG x (known) ← ← ← ← ← ← DPrG x(known) ← ← ← ← ← ← Dowanol ∘orange ← ← ← ← ← ← PM Dowanol ∘yellow ← ← ←← ← ← DPM Dowanol ∘ ← ← ← ← ← ← PnB Dowanol ∘ ← ← ← ← ← ← PMA Dowanol ∘← ← ← ← light light TPM yellow yellow Dowanol ∘ ← ← ← ← ← ← DPnB Dowanol∘ ← ← ← ← ← ← PPh Carbitol ∘ ← ← ← ← light light LG yellow yellow

0.2 g of “Plenact 238S” was added to 2 g of any organic solvent shown inTable 7, and properties were observed. The results are shown in Table10.

TABLE 10 Product Collection Product Amount name Manufacturer Structureamount name Manufacturer Structure added Hisolve TOHO Diethylene 2 gPlenact Ajinomoto Bis(dioctyl 0.2 g EDE Chemical glycol ethyl 238SFine-Techno pyrophosphate Industry Co., methyl ether ester)glycol Ltd.titanate Hisolve TOHO Polyethylene 2 g MPM Chemical glycol Industry Co.,dimethyl Ltd. ether Hisolve TOHO Tetraethylene 2 g MTEM Chemical glycolIndustry Co., dimethyl Ltd. ether Ethyl TOHO Ethyl lactate 2 g lactateChemical Industry Co., Ltd. PrG AGC Inc. Propylene 2 g glycol DPrG AGCInc. Dipropylene 2 g glycol Dowanol Dow Propylene 2 g PM Chemcial glycolCo., Ltd. monomethyl ether Dowanol Dow DiPropylene 2 g DPM Chemcialglycol Co., Ltd. monomethyl ether Dowanol Dow Propylene 2 g PnB Chemcialglycol Co., Ltd. n-butyl ether Dowanol Dow Propylene 2 g PMA Chemcialglycol Co., Ltd. monomethyl ether acetate Dowanol Dow Tripropylene 2 gTPM Chemcial glycol Co., Ltd. methyl ether Dowanol Dow DiPropylene 2 gDPnB Chemcial glycol Co., Ltd. n-butyl ether Dowanol Dow Propylene 2 gPPh Chemcial glycol Co., Ltd. phenyl ether Carbitol Dow Diethylene 2 gLG Chemcial glycol Co., Ltd. monoethyl ether Product Immediately After3After 1 After 2 After 4 After After 18 name after addition hr day daysdays 7 days days Hisolve ∘ ← ← ← ← ← ← EDE Hisolve ∘ ← ← ← ← ← ← MPMHisolve ∘ ← ← ← ← ← ← MTEM Ethyl ∘orange ← ← ← ← ← ← lactate PrG turbidgelationx ← ← ← ← ← DPrG turbid gelationx ← ← ← ← ← Dowanol ∘orange ← ←← ← ← ← PM Dowanol ∘yellow ← ← ← ← ← ← DPM Dowanol ∘ ← ← ← ← ← ← PnBDowanol ∘ ← ← ← ← ← ← PMA Dowanol ∘ ← ← ← ← light light TPM yellowyellow Dowanol ∘ ← ← ← ← ← ← DPnB Dowanol ∘ ← ← ← ← ← ← PPh Carbitol ∘ ←← ← ← light light LG yellow yellow

0.2 g of “Plenact 338X” was added to 2 g of any organic solvent shown inTable 7, and properties were observed. The results are shown in Table11.

TABLE 11 Product Collection Product Amount name Manufacturer Structureamount name Manufacturer Structure added Hisolve TOHO Diethylene 2 gPlenact Ajinomoto Bis(dioctyl 0.2 g EDE Chemical glycol ethyl 338XFine-Techno pyrophosphate Industry Co, methyl ether ester) glycol Ltd.titanate Hisolve TOHO Polyethylene 2 g MPM Chemical glycol Industry Co,dimethyl Ltd. ether Hisolve TOHO Tetraethylene 2 g MTEM Chemical glycolIndustry Co, dimethyl Ltd. ether Ethyl TOHO Ethyl lactate 2 g lactateChemical Industry Co, Ltd. PrG AGC Inc. Propylene 2 g glycol DPrG AGCInc. Dipropylene 2 g glycol Dowanol Dow Propylene 2 g PM Chemcial glycolCo, Ltd. monomethyl ether Dowanol Dow DiPropylene 2 g DPM Chemcialglycol Co., Ltd. monomethyl ether Dowanol Dow Propylene 2 g PnB Chemcialglycol Co., Ltd. n-butyl ether Dowanol Dow Propylene 2 g PMA Chemcialglycol Co., Ltd. monomethyl ether acetate Dowanol Dow Tripropylene 2 gTPM Chemcial glycol Co., Ltd. methyl ether Dowanol Dow DiPropylene 2 gDPnB Chemcial glycol Co., Ltd. n-butyl ether Dowanol Dow Propylene 2 gPPh Chemcial glycol Co., Ltd. phenyl ether Carbitol Dow Diethylene 2 gLG Chemcial glycol Co., Ltd. monoethyl ether Product Immediately After3After 1 After 2 After 4 After 7 After 18 name after addition hr day daysdays days days Hisolve ∘ ← ← ← ← ← ← EDE Hisolve ∘ ← ← ← ← ← ← MPMHisolve ∘ ← ← ← ← ← ← MTEM Ethyl ∘orange ← ← ← ← ← ← lactate PrG turbidgelationx ← ← ← ← ← DPrG turbid gelationx ← ← ← ← ← Dowanol ∘ orange ← ←← ← ← ← PM Dowanol ∘yellow ← ← ← ← ← ← DPM Dowanol ∘ ← ← ← ← ← ← PnBDowanol ∘ ← ← ← ← ← ← PMA Dowanol ∘ ← ← ← ← ← ← TPM Dowanol ∘ ← ← ← ← ←← DPnB Dowanol ∘ ← ← ← ← ← ← PPh Carbitol ∘ ← ← ← ← ← ← LG

0.2 g of a substance represented as “OTC-7” in Table 2 was added to 2 gof any organic solvent shown in Table 7, and properties were observed.The results are shown in Table 12.

TABLE 12 Product Collection Product Amount name Manufacturer Structureamount name Manufacturer Structure added Hisolve TOHO Diethylene 2 gOrgatix Matsumoto diisoproxy 0.2 g EDE Chemical glycol ethyl TC400 Finetitanium Industry Co., methyl ether Chemical bis(triethanol Ltd. Co.,Ltd. aminate) Hisolve TOHO Polyethylene 2 g MPM Chemical glycol IndustryCo., dimethyl Ltd. ether Hisolve TOHO Tetraethylene 2 g MTEM Chemicalglycol Industry Co., dimethyl Ltd. ether Ethyl TOHO Ethyl 2 g lactateChemical lactate Industry Co., Ltd. PrG AGC Inc. Propylene 2 g glycolDPrG AGC Inc. Dipropylene 2 g glycol Dowanol Dow Propylene 2 g PMChemcial glycol Co., Ltd. monomethyl ether Dowanol Dow DiPropylene 2 gDPM Chemcial glycol Co., Ltd. monomethyl ether Dowanol Dow Propylene 2 gPnB Chemcial glycol Co., Ltd. n-butyl ether Dowanol Dow Propylene 2 gPMA Chemcial glycol Co., Ltd. monomethyl ether acetate Dowanol DowTripropylene 2 g TPM Chemcial glycol Co., Ltd. methyl ether Dowanol DowDiPropylene 2 g DPnB Chemcial glycol Co., Ltd. n-butyl ether Dowanol DowPropylene 2 g PPh Chemcial glycol Co, Ltd. phenyl ether Carbitol DowDiethylene 2 g LG Chemcial glycol Co, Ltd. monoethyl ether ProductImmediately After3 After 1 After 2 After 4 After After 18 name afteraddition hr day days days 7 days days Hisolve X (known) ← ← ← ← ← ← EDEHisolve X (known) ← ← ← ← ← ← MPM Hisolve X (known) ← ← ← ← ← ← MTEMEthyl ? ? ? x ← ← ← lactate yellow/ yellow/ yellow/ yellow/ turbidturbid turbid turbid PrG ◯ ← ← ← ← ← ← (known) DPrG ◯ ← ← ← ← ← ←(known) Dowanol ? ◯ ← ← ← ← ← PM yellow/ yellow/ turbid clear Dowanol ?◯ ← ← ← ← ← DPM yellow/ yellow/ turbid clear Dowanol ◯ ← ← ← ← ← ← PnBDowanol ? turbid ? turbid ? turbid xturbid ← ← ← PMA Dowanol ◯ ← ← ← ←light light TPM yellow yellow Dowanol ◯ ← ← ← ← ← ← DPnB Dowanol ◯ ← ← ←← ← ← PPh Carbitol ◯ ← ← ← ← light light LG yellow yellow

Example 5

A metal-particle dispersion composition containing 3 g of water, 2 g ofany organic solvent shown in Table 7, 1 g of any of the above phosphoricacid organic titanate compounds, and 3 g of metal particles representedas “MP-1” in Table 3 was prepared. The metal-particle dispersioncomposition obtained in this manner was put into a sample bottle(capacity: 14 ml) that can be fitted and sealed with a lid, and stirredin a sealed state for 1 minute under a room temperature environment.After stirring, the sample was left and observed on a daily basis andstability was evaluated. The evaluation results are shown in Table 13 toTable 15 respectively illustrated in FIGS. 1-3. In Table 13 to Table 15,a result with a numerical value indicated as “finished” means thatdecrease in stability was confirmed after storage for the number of daysindicated by the number, and evaluation was completed. On the otherhand, the expression “ongoing” means that no decrease in stability wasobserved even after storage for the number of days (34 days, 35 days)shown in Table 13 to Table 15.

Example 6

A metal-particle dispersion composition containing 3 g of water, 2 g ofHisolve MTEM shown in Table 7, 3 g of any metal particle shown in Table3, and 0.2 g of Plenact 38S or Plenact 238S was prepared (Table 16 toTable 19). In addition, a metal-particle dispersion composition havingthe same composition but containing none of Plenact 38S and Plenact 238Swas prepared (Table 16 to Table 19).

TABLE 16 Organic Organic chelate Metal Evaluation Confirmation solventcompound particles result date OS-2 Not contained MP-20 Generated 1Plenact 38S Generated 1 Not contained MP-17 Generated 1 Plenact 38SGenerated 4 Not contained MP-12 Generated 2 Plenact 38S Not generated 21Not contained MP-21 Generated 4 Plenact 38S Generated 8 Not containedMP-22 Generated 0.5 Plenact 38S Not generated 21 Not contained MP-2Generated 0.5 Plenact 38S Generated 1 Not contained MP-3 Generated 0.5Plenact 38S Not generated 21 Not contained MP-4 Generated 0.5 Plenact38S Not generated 22 Not contained MP-13 Generated 11 Plenact 38S Notgenerated 21 Not contained MP-14 Generated 2 Plenact 38S Not generated21 Not contained MP-5 Generated 11 Plenact 38S Not generated 21

TABLE 17 Organic Organic chelate Metal Evaluation Confirmation solventcompound particles result date OS-2 Not contained MP-6 Generated 1Plenact 38S Not generated 21 Not contained MP-7 Generated 0.5 Plenact38S Generated 6 Not contained MP-8 Generated 11 Plenact 38S Generated 4Not contained MP-16 Generated 0 Plenact 38S Not generated 5 Notcontained MP-23 Generated 0.5 Plenact 38S Generated 5 Not contained MP-9Generated 0 Plenact 38S Not generated 34 Not contained MP-24 Generated 4Plenact 38S Not generated 21 Not contained MP-25 Generated 2 Plenact 38SNot generated 21 Not contained MP-10 Generated 3 Plenact 38S Notgenerated 21 Not contained MP-15 Generated 3 Plenact 38S Not generated21

TABLE 18 Organic Organic chelate Metal Evaluation Confirmation solventcompound particles result date OS-2 Not contained MP-17 Generated 1Plenact 238S Generated 4 Not contained MP-12 Generated 2 Plenact 238SNot generated 21 Not contained MP-21 Generated 4 Plenact 238S Notgenerated 21 Not contained MP-22 Generated 0.5 Plenact 238S Notgenerated 21 Not contained MP-2 Generated 0.5 Plenact 238S Generated 4Not contained MP-3 Generated 0.5 Plenact 238S Not generated 21 Notcontained MP-4 Generated 0.5 Plenact 238S Not generated 21 Not containedMP-13 Generated 11 Plenact 238S Not generated 21 Not contained MP-14Generated 2 Plenact 238S Not generated 21 Not contained MP-5 Generated11 Plenact 238S Not generated 21

TABLE 19 Organic Organic chelate Metal Evaluation Confirmation solventcompound particles result date OS-2 Not contained MP-6 Generated 1Plenact 238S Not generated 21 Not contained MP-7 Generated 0.5 Plenact238S Generated 6 Not contained MP-8 Generated 11 Plenact 238S Notgenerated 21 Not contained MP-16 Generated 0 Plenact 238S Generated 0Not contained MP-23 Generated 0.5 Plenact 238S Generated 11 Notcontained MP-9 Generated 0 Plenact 238S Generated 19 Not contained MP-24Generated 4 Plenact 238S Not generated 21 Not contained MP-25 Generated2 Plenact 238S Not generated 21 Not contained MP-10 Generated 3 Plenact238S Not generated 21 Not contained MP-15 Generated 3 Plenact 238S Notgenerated 21

The obtained metal-particle dispersion composition was put into a samplebottle (capacity: 14 ml) that can be fitted and sealed with a lid, andstirred in a sealed state for 1 minute under a room temperatureenvironment. After stirring, the sample was left, and it was checkedwhether generation of a gas was visually observed. When generation of agas was confirmed, the column of the evaluation result in Table 16 toTable 19 was set as “generated,” and the column of confirmation date wasset as “0.” After 12 hours from when it was left, it was visuallychecked whether generation of a gas was observed. When generation of agas was confirmed, the column of the evaluation result in Table 16 toTable 19 was set as “generated,” and the column of confirmation date wasset as “0.5.” Thereafter, generation of a gas was visually checked oncea day, and when generation of a gas was confirmed, the column of theevaluation result in Table 16 to Table 19 was set as “generated,” andthe number of days since it was first left until generation of a gas wasconfirmed is shown in the column of confirmation date. When nogeneration of a gas was confirmed even after a predetermined number ofdays had passed, the column of the evaluation result in Table 16 toTable 19 was set as “not generated,” and the column of confirmation dateindicates the number of days since it was first left before the finalconfirmation date.

Table 20 shows the calculation results of the solubility from thesolubility product of various metal elements.

TABLE 20 Solubility product (Chemical Calculated Type of Assumedphosphate Handbook Revised solubility element Structure Mw 2nd Edition)mol/L g/L Ag Ag₃PO₄ 418.58 1.30E−20 4.77E−08 Al AlPO₄ 121.95 3.90E−117.62E−04 Co Co₃ (PO₄) 366.73 1.80E−35 1.56E−15 Cr CrPO₄·4H₂O 218.972.40E−23 1.07E−09 Cu Cu₃ (PO₄)₂ 380.59 1.30E−37 1.37E−16 Fe FePO₄ 150.821.30E−22 1.72E−09 Fe₃ (PO₄)28H₂O 501.6 — — SUS304 — — — — In InPO₄209.79 2.20E−22 3.11E−09 Mn MnPO₄·H₂O 167.9 — — V V₃ (PO₄)₅ 627.7 — — ZnZn₃ (PO₄)₂ 386.08 9.10E−33 3.68E−14 Zn₃ (PO₄)₂·4H₂O 458.2 — — Ni Ni₃(PO₄)₂ 366.01 5.30E−31 2.66E−13 Ni₃ (PO₄)₂·8H₂O 510.1 — — Sn SnHPO₄214.7 — — Ti Ti₃ (PO₄)₄ 523.5 — —

In addition, Table 21 shows literature data related to the solubility.

TABLE 21 Determination of solubility (Chemical Type of Assumed phosphateHandbook Revised 5th element Structure Mw Edition) Ag Ag₃PO₄ 418.58Poorly soluble Al AlPO₄ 121.95 Insoluble Co Co₃ (PO₄) 366.73 InsolubleCr CrPO₄·4H₂O 218.97 Insoluble Cu Cu₃ (PO₄)₂ 380.59 Insoluble Fe FePO₄150.82 Poorly soluble Fe₃ (PO₄)28H₂O 501.6 Insoluble SUS304 — — — InInPO₄ 209.79 — Mn MnPO₄·H₂O 167.9 Insoluble V V₃ (PO₄)₅ 627.7 — Zn Zn₃(PO₄)₂ 386.08 — Zn₃ (PO₄)₂·4H₂O 458.2 Insoluble Ni Ni₃ (PO₄)₂ 366.01 —Ni₃ (PO₄)₂·8H₂O 510.1 Insoluble Sn SnHPO₄ 214.7 Insoluble Ti Ti₃ (PO₄)₄523.5 —

The invention claimed is:
 1. A metal-particle dispersion compositioncontaining, based on the entire composition, 10 to 80 mass % of metalparticles, 0.01 to 10 mass % of an organic titanate compound, 1 to 40mass % of water, and 2 to 30 mass % of an organic solvent having ahigher boiling point than water, wherein the organic titanate compoundconsists of at least one compound selected from the group consisting ofisopropoxy tri(dioctyl pyrophosphate)titanate, bis(dioctylpyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylenetitanate, and isopropyl tri(dioctyl pyrophosphate) titanate, and whereinthe organic solvent having a higher boiling point than water has 7 to 20carbon atoms and has a plurality of ether bonds.
 2. The metal-particledispersion composition according to claim 1, wherein the number of etherbonds contained in the organic solvent having a higher boiling pointthan water is 3 or more.
 3. The metal-particle dispersion compositionaccording to claim 1, wherein the organic solvent having a higherboiling point than water contains a smaller number of hydroxyl groupsthan the number of ether bonds.